Willow Creek Reservoir Report
Nearby: Bill Welk Dam Frederick
Last Updated: December 13, 2025
Willow Creek, located in Westport, South Dakota, is a vital water resource managed by the local government with oversight from the South Dakota Department of Agriculture and Natural Resources.
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Summary
The dam, constructed in 1934 by the Works Progress Administration (WPA), stands at a height of 49 feet and has a storage capacity of 7,650 acre-feet. With a drainage area of 155 square miles, the dam serves as a crucial flood control and water supply structure for the region.
The dam's spillway, with a width of 120 feet, is uncontrolled, allowing for the release of excess water during peak flow events. Willow Creek Dam is classified as having a high hazard potential, but its current condition is assessed as fair. Regular inspections are conducted every three years to ensure the dam's structural integrity and safety. Although the risk assessment indicates a moderate level of risk, the dam is equipped with vertical lift outlet gates to manage water levels effectively.
The presence of Willow Creek Dam underscores the importance of effective water resource management in mitigating flood risks and ensuring reliable water supplies for the surrounding community. Climate enthusiasts and water resource stakeholders can appreciate the dam's engineering design and the collaborative efforts involved in its operation and maintenance to safeguard the local ecosystem and residents from potential hazards.
Year Completed |
1934 |
Dam Length |
1330 |
Dam Height |
49 |
River Or Stream |
WILLOW CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
45 |
Drainage Area |
155 |
Nid Storage |
7650 |
Outlet Gates |
Vertical Lift |
Hazard Potential |
High |
Foundations |
Soil |
Nid Height |
49 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Elm R At Westport Sd
|
12cfs |
Foot Creek Near Aberdeen
|
0cfs |
James R At Columbia Sd
|
268cfs |
Maple R At Nd-Sd State Line
|
5cfs |
James River At Nd-Sd State Line
|
194cfs |
James R Near Stratford Sd
|
409cfs |
Dam Data Reference
Condition Assessment
SatisfactoryNo existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
Fair
No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
Poor A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency. Investigations and studies are necessary.
Unsatisfactory
A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
Not Rated
The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Not Available
Dams for which the condition assessment is restricted to approved government users.
Hazard Potential Classification
HighDams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
Significant
Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environment damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
Low
Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
Undetermined
Dams for which a downstream hazard potential has not been designated or is not provided.
Not Available
Dams for which the downstream hazard potential is restricted to approved government users.
Willow Creek